Fuel supply



INVENTOR.

F I G.

Sept. 22, 1959 H. EBERHARDT FUEL SUPPLY Filed Jan. 8, 1958 BYg/ ATTORNEY 2 z w w W ax M m m m7 F I 5 E ,l B a w n /yvfiw w i m nun. G a 4 nemflfleuw 5 F U ted s I: if i I 11 Industries, Incorporated, New York, N.Y., a corporation'ofNew Jersey Application January 8, 1958, Serial No. 707,778

6 Claims. (Cl. 261-36) This invention relates to fluid handling systems, and more particularly to a system for reducing the pressure of fuel delivered to a carburetor Or other fuel dispensing apparatus during idle operation of an internal combustion engine, and to a valve associated therewith.

' When an engine is operating at normal or high speeds, it:requires substantially great quantities of fuel which are supplied from a fuel pump to a fuel dispensing apparatus such as a carburetor. During idle operation of the engine, a much smaller quantity of fuel is required. A differential in pressure between the outlet of the pump and the inlet of the carburetorcauses the fuel to move from the pump to the carburetor. The pump is normally of the constant pressure type, and during hot idle opera-v tion the pressure in the fuel line between the pump and the inlet may become sufficiently high to force open a valve in the inlet, against the force of a float. or other device. which normally controls the opening and. closing of the float. During hot idle operation such pressure.

maybe sufficient to force excessive quantities of fuel past the engine. 1 e I It is therefore an object of this invention to reduce the fuel pressure delivered to a carburetor or other fuel dis pensing apparatus only during idle operation of the system. v

vAnother object of this invention 'isto reduce the fuel pressure delivered to a carburetor or other fuel dispensing apparatus only during idle operation, and to prevent vapor lock in the fuel lines.

Another object of this invention is to reduce exces sively .high pressure of hot fuel at an engine fuel dispensing apparatus, especially during idle operation of the engine. i r Another object of this invention is to reduce fuel pressure, in a fuel system having a valve controlling the admission of fuel to a fuel dispensing device,-suificiently to prevent the pressure of the fuel from prematurely opening the valve other than in responseto the requirements of the dispensing device. Another object of this invention is to provide an improved fuel system for an internal combustion engine.

Another object of this'invention is to provide an improved pressure reducing valve. Additional objects and advantages will be apparent from the following description and drawings, in which:

-Fig.-1 is a schematic side view of an internal com-' bustion engine, and illustrates an embodiment of the invention; a 1

Fig. 2 is a schematic side-view of a carburetor illustrating another embodiment of the invention.

Fig. 3 is a schematic side view to an enlarged scale of a portion of the embodiment illustrated in Fig; 1. j Briefly, the invention relates to afuel system forginternal combustion engines inwhich idle-operation of the system causes a'reduction in fuel pressure by closing a restriction in a fuel line, and more specifically in a carburetion system wherein closing the throttle valve to the float valve, causing flooding'and possible stalling of 2 e the-.idle position actuates a-metering valve forming an additional restriction in the fuel line between a fuel pump and the carburetor fuel inlet.

Referring to Fig. l, the fuel system of an engine 1 includes a fuel tank 2,a constant pressure fuel pump 3,

a pressure reducing valve, assembly 4, a carburetor 5,

an intake manifold 6, an exhaust manifold 7 so arranged as to form a hot spot in the general vicinity 9 of the intake manifold 6, an exhaust pipe 8, and suitable fuel lines, as follows: The outlet of the fuel tank 2 is joined to the inlet of the fuel pump 3 by a conduit 12. The outlet of the fuel pump 3 is provided with a check valve to prevent backflow into the pump, and is joined to the pressure reducing valve 4' by a conduit 13. A conduit 14 joins the pressure reducing valve 4 and the source of fuel supply. The return line 14 may be connected to the tank 2 as illustrated, or to any portion of the source of supplyf which is herewith defined as including the fuel tank, the intake portion of the fuel pump, and the fuel conveying system between the tank and the inlet of the pump, as conduit 12.

Referring now to Fig. 2, the carburetor 5 includes a cover 17, a body 18, and a base 19 including a flange 20 for securing the carburetor 5 to.,the intake manifold 6 in any conventional manner, as by bolts (not shown).

. An induction or mixture conduit 23 passes through the cover 17, body 18,-. andbase 19. The induction conduit 23 includes a venturi cluster 24 in the body portion of the carburetor. A choke valve 25 is fixed on a shaft 26 in the induction conduit 23, and the shaft is rotatably mounted in the cover 17. The choke 25- may be actuated in any conventional manner, and is substantially closed during starting and warm-up of the engine 1, and is fully open when the engine has reached its normal operating temperature. Mounted in the induction conduit-23 in the base portion 19 is a throttle valve 29 fixed to a shaft 30 rotatably mounted in the base portion. Fixed to the throttle shaft 30 is a lever 31 having an adjusting screw 32; The throttle valve may be actuated,

in any conventional manner (not shown), as by a lever and alinkage to a conventional accelerator pedal.

. The carburetor fuel system includes a fuel bowl 35 having pivotally mounted therein a float 36. Fixed to float 36 is an-arm 37 which engages a needle valve 38 to close the needle valve at a predetermined level of fuel in the bowl 35, and to permit the needle valve 38 to open when the levelof the fuel in the bowl falls below the predetermined level. Fuel is discharged from the fuel bowl 35 through a main orifice 40 receiving a metering rod 41- which permits a reduced quantity of fuel to pass through the orifice during idle operation of the engine 1, and to permit a greater quantity of fuel to pass through the orifice during normal and high-speed operation of the engine, responsive for instance, to closing and opening movement, respectively, of the throttle valve 29. During idle operation of ;the engine, the greatest restriction is"provided in the main orifice 40 by the metering rod- 41. .Fuel is drawn through the main'fuel passage 42, into the idle tube 43, through passage system 44,- into chamber 45, and intothe induction conduit 23 through a port (not shown) opening into the chamber 45. During idle operation the throttle 29 is substantially closed ,and the fuel is' drawn through the port, which has an opening downstream of the edge of the throttle, by' the direct action of engine suction. During normal and high-speed operation, the throttle 23 is open, withdrawing the metering rod 41 partway from the orifice 40, allowing a greater volume of fuel to flow into the main fuel passage. 42 and out through the main nozzle 48, responsive to the flow of air through the venturi cluster 24in the induction conduit 23. Air which is drawnthrough the induction conduit 23 first passes through an Patented Sept. 22, 1959.

air cleaner (not shown) attached to a fiange on an air needle valve. The valve assembly 4 also includes a cap' 58 secured to the body 51 in any suitable manner asby bolts (not shown). A diaphragm seal 60 is clamped between the body 51 and the cap 58. A valve 61 is received in the fuel chamber 52 and has one end reduced and secured to the diaphragm in any appropriate manner as by peening over the end of the reduced portion. A pair of washers 63 protect the faces of the diaphragm. The other end of-the valve 61 is tapered as at 64,- and'has a stem 65. A function of the stem 65 is to maintain proper alignment of the tapered restriction 64 on the valve 61 and the restriction 54 in the valve body- 51. A spring 66 is received between a shoulder in the fuel chamber 52 adjacent the restriction 54 and the top washer 63 to'urge the valve 61 downwardly so that onlythe stem 65 is received in the restriction 54. A plunger 70 is slidably received in a hole through the cap 58, and has a flange 71 to retain the plunger in the cap. A lever 73 is pivotally mounted on the carburetor by a pivot pin 74 passing through holes in cars 75 on a carburetor fuel chamber and a hole 76 in the lever 73. The lever may assume any appropriate configuration having an end 77 engaging the set screw 32 on link 31 which is fixed to throttle shaft 30, as previously mentioned. The set screw engages the end 77 of the lever 73 only when the throttle 29 is in or close to the closed or idle position. The other end 78 of the lever 73 presses against the plunger 70, moving it upwardly to move the valve 61 against the resilient force of the spring 66, thereby moving the tapered portion 64 of the valve into the restriction 54 in the valve body 51, reducing the flow and pressure of the fuel through the inlet 53 and into the fuel chamber 52.

Referring to Fig. 3, similar reference numeralsrefer to similar parts, and the structure is identical with that shown in Fig. 2, with the addition of a second outlet 81 in the valve body 51. The outlet 81 is threaded to re ceive a connection on return conduit 14. A restriction 82 is received in the outlet 81 for controlling the flow of fluid therethrough and maintaining an adequate pressure in the fuel chamber 52.

The operation of the device, with particular reference to the embodiment illustrated in Fig. 2, is as follows: Fuel in tank 2 is drawn through conduit 12 by a pump 3 and is discharged from the pump into the conduit 13 at a pressure of between 2 and p.s.i.-for example, 5 p.s.i.and passes into the inlet 53 of the valve 4. Fuel in the fuel chamber is at about atmospheric pressure. During normal and high-speed operation of the engine 1 the stem 65 on the valve 61 is the sole restriction in the restriction 54', thereby permitting a relatively great flow of fuel at a substantially highpressure into the fuel chamber 52. As the carburetor 5 is discharging a substantially great volume of fuel through the main nozzle 48, a relatively high pressure is required in fuel chamber 52 to provide an adequate volume of fuel. During normal and high-speed operation, the throttle valve 29 is open.

When the throttle valve 29 is substantially closed, during idle, the set screw 32 engages the end 77 of the lever 73, moving the other end 78 of the lever upwardly against the plunger '70, thereby moving the valve 61 upwardly against the resilient force of the spring 66 and moving the tapered restriction 64 into the restriction 54, substantially reducing the flow of fuel through the restriction 54 and thereby reducing the pressure in the fuel chamber 52. Any excess pressure developed in sup-' ply line 13 by hot, slow moving fuel will not be applied against the needle valve 38. Thus there is a substantially lower pressure on the needle valve 38, reducing the tendency of the fuel pressure to open the needle valve against the force of the float 36 and possibly bending the arm 37. In this embodiment, as long as fuel is flowing through the valve outlet 55,? the pressure in fuel chamber 52 will be reduced during idle operation of the engine 1.

The operation of the embodiment shown in Fig. 3 is the same as the operation-previously described, withv the addition of a fuel escape through outlet 81 and restriction .82. The outlet 81 permits an excessive pressure in the fuel chamber 52, which may build up when the engine is stopped and no fuel is flowing through the outlet 55, to be dissipated. The outlet 81 further permits vapors which may accumulate in the fuel chamber 52, or conduit 13, to escape. The escaping vapors and liquid fuel flow through conduit 14 and back to the source of supply,

either tank 2, conduit 12, or the intake portion of pump 3'.

Although the invention has been described with particular reference to certain embodiments, features, and particular functional relationships, various changes in keeping with the objects of the invention will be apparent to one skilled in the art, and the invention is therefore not to be limited to such embodiments, features, and functional relationships except as set forth in the appended claims.

l claim:

1 A charge'forming device for supplying fuel to an internal combustion engine from a constant pressure source comprising a mixture conduit, a throttle valve in said conduit for restricting air flow therethrough, a fuel chamber having an inlet for connecting with said con stant pressure fuel source, a control valve in the inlet to the chamber movable to a position to limit the rate of flow of fuel into the chamber, a fuel bowl supplied with fuel from said chamber, said bowl having a float controlled valve for maintaining the fuel level therein and orifices for discharging fuel into the mixture conduit, and

pressure fuel source, a tapered control valve projecting into the inlet to the chamber movable to a position to limit the rate of flow of fuel into the chamber, a fuel bowl" supplied with fuel from said chamber, said bowl having a float controlled valve for maintaining the fuel level therein and orifices for discharging fuel into the mixture conduit, and a mechanical linkage interconnecting the control and throttle valves for moving the control valve to its fuel flow limiting position when the throttle valve is in its closed position thereby protecting the float controlled valve by decreasing the pressure in thechamber at low fuel flow.

3. A charge forming device for supplying fuel to an internal combustion engine from a constant pressure source comprising a mixture conduit, a throttle valve in said conduit for restricting air flow therethrough, a'fnel' chamber having an inlet for connecting with said constant pressure fuel source, a control valve in the inlet to the chamber movable to a position to limit the rate of flow of fuel into the chamber, a biasing member for opening said control valve, a fuel bowl supplied with fuel from said chamber, said bowl having a float controlled valve for maintaining the fuel level therein and orifices for discharging fuel into the mixture conduit, and a mechanical linkage interconnecting the control and throttle valves for moving the control valve to its fuel flow limiting position in opposition to said biasing member when the throttle valve is in its closed position thereby protecting the float controlled valve by decreasing the pressure in the chamber at low fuel flow.

4. A charge forming device for supplying fuel to an internal combustion engine from a constant pressure source comprising a mixture conduit, a throttle valve in said conduit for restricting air flow therethrough, a fuel chamber having an inlet for connecting with said constant pressure fuel source, a control valve in the inlet to the chamber movable to a position to limit the rate of flow of fuel into the chamber, a biasing member for opening said control valve, a fuel bowl supplied with fuel from said chamber, said bowl having a float controlled valve for maintaining the fuel level therein and orifices for discharging fuel into the mixture conduit, and a mechanical arm abutting the control and throttle valves engaging said control and throttle valves when the throttle valve is in its closed position thereby opposing said biasing member and placing said control valve in its flow limiting position and protecting the float controlled valve by decreasing the pressure in the chamber at low fuel flow.

5. A charge forming device for supplying fuel'to an internal combustion engine from a constant pressure source comprising a mixture conduit, a throttle valve in said conduit for restricting air flow therethrough, a fuel chamber having an inlet for connecting with said constant pressure fuel source, a control valve in the inlet to the chamber movable to a position to limit the rate of flow of fuel into the chamber, an outlet in said fuel chamber communicating with said constant pressure source to return fuel to said constant pressure source, a fuel bowl supplied with fuel from said chamber, said bowl having a float controlled valve for maintaining the fuel level therein and orifices for discharging fuel into the mixture conduit, and a mechanical linkage interconnecting the control and throttle valves for moving the control valve to its fuel flow limiting position when the throttle valve is in its closed position thereby protecting the float controlled valve by decreasing the pressure in the chamber at low fuel flow.

6. A charge forming device for supplying fuel to an internal combustion engine from a constant pressure source comprising a mixture conduit, a throttle valve in said conduit for restricting air flow therethrough, a fuel chamber having an inlet for connecting with said constant pressure fuel source, a control valve in the inlet to the chamber movable to a position to limit the rate of flow of fuel into the chamber, a restricted outlet in said fuel chamber communicating with said constant pressure source and permitting limited fuel flow thereto, a fuel bowl supplied with fuel from said chamber, said bowl having a float controlled valve for maintaining the fuel level therein and orifices for discharging fuel into the mixture conduit, and a mechanical linkage interconnecting the control and throttle valves for moving the control valve to its fuel flow limiting position when the throttle valve is in its closed position thereby to protect the float controlled valve by decreasing the pressure in the chamber at low fuel flow.

Smith Oct. 13, 1936 Carlson et al Oct. 26, 1954 

